Alternators, and particularly vehicular, automotive-type alternators, usually have a housing therefor which retains bearings for the operating shaft of the machine. The housing customarily includes a pair of bell or cup-shaped ends which have the bearings secured therein. Frequently, diodes which are provided to rectify the a-c output from the alternator are also fitted into the housing, by press-fitted or interference-fitted in suitable openings formed in one of the end bells or end covers forming the housing. If the end bells are cup-shaped, it is difficult to insert the diodes and frequently it is not economical to fit them directly into the end bells. Manufacture of the end bells themselves is restricted to only a few manufacturing processes, for example mold casting, injection casting, or die casting.